no server suitable for synchronization found For NTP Service

Question

I had to build ntp packages from the source and install all of them on some hosts. After the installation, ntpdate 1.us.pool.ntp.org works for the synchronization. However, when I tried to do ntpdate <ip_add_of_another_host> it shows me the following error

21 Jul 18:57:53 ntpdate[18287]: no server suitable for synchronization found

Even more weirdly, sometimes ntpdate <ip_addr_of_another_host> works after I try the ntpdate 1.us.pool.ntp.org

My configuration file of the ntp server:

# /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help

driftfile /var/lib/ntp/ntp.drift


# Enable this if you want statistics to be logged.
#statsdir /var/log/ntpstats/

statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable
# Specify one or more NTP servers.

# Use servers from the NTP Pool Project. Approved by Ubuntu Technical Board
# on 2011-02-08 (LP: #104525). See http://www.pool.ntp.org/join.html for
# more information.
server 127.1.1.0 # local clock
fudge 127.1.1.0 stratum 10
# Access control configuration; see /usr/share/doc/ntp-doc/html/accopt.html for
# details.  The web page <http://support.ntp.org/bin/view/Support/AccessRestrictions>
# might also be helpful.
#
# Note that "restrict" applies to both servers and clients, so a configuration
# that might be intended to block requests from certain clients could also end
# up blocking replies from your own upstream servers.

# By default, exchange time with everybody, but don't allow configuration.
restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery

# Local users may interrogate the ntp server more closely.
restrict 127.0.0.1
restrict ::

I also tried the default configuration when I did apt-get install ntp, but it does not work as well.

Answer 1

You could try ntpdate -buv 1.us.pool.ntp.org

-b is for when your machine is out of sync for more than 1000s

-u makes ntpdate use unprivileged ports

-v is for verbosity.

The respons on my system changes from the same error:

no server suitable for synchronization found

into:

19 Dec 21:36:46 ntpdate[18781]: ntpdate [email protected] Sun Sep 7 08:14:50 UTC 2014 (1)

19 Dec 21:36:45 ntpdate[18781]: step time server 194.109.22.18 offset -6.540448 sec